Robert Boschgmbh

Rainer Bone

Rudolf Nagel

Bernward Boning

Franz Sellmaier

Gunter Honig

Erich Schneider

Winfried Moser

Uwe Kiencke

Martin Klenk

Dieter-Andreas Dambach

Helmut Reum

Jorg Lange

Joachim Braunger

Imanuel Krauter

Jens-Detlef Rubrecht

Jog Lange

Bernward B/o/ Ning

In a method and device for monitoring a secondary-air system, a first value is determined which characterizes the secondary air stream blown by the secondary-air system into the exhaust-gas channel of an internal combustion engine. On the basis of this first value, the functioning of the secondary-air system is judged. If the first value lies within a predeterminable interval, it is concluded that the secondary-air system is operating properly. If the first value, on the other hand, lies outside of this predeterminable interval, it is concluded that a malfunction is present. The first value is determined from a second value which characterizes the stream of air fed to the internal combustion engine, from the air/fuel ratio of the mixture drawn in by the internal combustion engine, and from the air/fuel ratio prevailing in the exhaust-gas channel downstream of the place of introduction of the secondary-air line.

Method and device for monitoring a secondary-air system of a motor

The emission of toxic materials when starting an internal combustion engine equipped with a catalytic converter and a secondary air pump can be further reduced with the method and arrangement of the invention. This reduction takes place by a switch-on of the secondary air pump under selectable conditions which include a warm start of the engine. The danger of overheating the catalytic converter by the operation of the secondary air pump for a warm engine is taken into account by a variable switch-on duration of the secondary air pump which can be realized by a counting procedure having an increment dependent on operating parameters.

Method and arrangement for controlling the operation of a secondary air

To obtain higher current yield from ion current measurable across the electrodes of a spark plug upon application of a biasing potential thereto, occurring immediately after an ignition event due to ionization of burning hydrocarbons within the combustion chamber of an internal combustion engine (ICE), the polarity of the circuit including a spark plug is so selected that the smaller one of the electrodes, typically the center electrode of the spark plug, has a positive measuring voltage and positive ignition voltage applied thereto so that the positively charged ions, which have a substantially greater mass than the electrons, will be caused to flow to the negatively charged substantially greater electrode, thus resulting in an enhanced ion current. A standard automotive ignition circuit can be used, with the battery connected, as customary, with negative-ground (FIG. 3) by reversely connecting the secondary of the ignition coils--with respect to customary connection--to the center electrode of the spark plug. An auxiliary biasing battery can be avoided by charging a capacitor, for example from the ignition system, to provide measuring energy.

Internal combustion engine combustion chamber pressure sensing apparatus

The output of a combustion chamber sensor is analyzed in two succeeding time intervals defined in term of crankshaft position by use of a reference mark. The sensor output is compared with prescribed threshold values in the respective intervals, and a logic circuit recognizes whether normal combustion, slow combustion or a combustion failure is present and an engine control, such as fuel injection or ignition timing, or a combination of both is modified accordingly.

Control of an internal combustion engine with reference to a combustion

A light guide element, secured in a spark plug-like housing and positioned, for example, within a metallic tube forming a spark plug connector, is coated at the end facing the combustion chamber with a light-impervious material viz: graphite, the graphite emitting radiation upon influence of heat arising within the combustion chamber, which radiation is transmitted to the optical pick-up for subsequent photo-electric evaluation thereof. The optical pick-up is, for example, a quartz glass rod coupled to a light guide cable, or directly coupled to an opto-electrical transducer.

Optical combustion event sensor structure particularly knock sensor for

In order to eliminate from an ion current sensor signals which are not derived from knocking of an engine, the ion current sensor signal is evaluated by a high-pass - low-pass filter to filter out signals of frequencies extraneous to knocking frequencies, using, preferably, a digital filter including two timing stages (11, 13) connected to a counter; to inhibit response of the circuit, an interrupter switch (8) is included in the evaluation circuit, which is opened upon sensing of disturbance signals due to ignition events, for example upon occurrence of ignition, by setting a timing stage (20) which maintains the switch open, and thus inhibits evaluation of oscillatory signals from the ion current sensor (1) for the timing duration thereof. To store previously counted oscillatory signals, a further timing stage (21) can be provided, likewise connected to the ignition signal and enabled at the initiation of current flow through the primary of an ignition coil to prevent resetting of the counter for the timing duration thereof.

Internal combustion engine knock sensing system

The leading edge of each pulse of an incoming signal sequence starts a first monostable multivibrator whose period is equal to the period of the pulse sequence when the pulse sequence has the desired frequency. The input signal sequence and the output signal from the multivibrator are applied to two inputs of an exclusive OR gate. The latter furnishes an output signal corresponding to the difference in pulse width between the signal applied to the two inputs. The leading edge of the difference signal then starts a second monostable multivibrator whose pulse width corresponds to the maximum allowable frequency deviation. The output signal of the second monostable multivibrator is applied to an inverting input of an AND gate. The direct input of the AND gate receives the difference signal. The AND gate, therefore, only furnishes an output signal when the difference signal has a greater pulse width than the output signal of the second multivibrator, i.e. when the frequency deviation in the incoming signal sequence exceeds the maximum permissible frequency deviation.

Simplified monitoring apparatus for sensors in motor vehicles

Signals from a coil producing pulses in response to flux variations produced by a rotary member driven by an engine crankshaft are applied in push-pull through series resistors to the inverting and non-inverting inputs of a comparator. A variable voltage divider for the input signals is provided by a pair of complementary transistors respectively connecting the comparator inputs to opposite poles of a fixed voltage supply. The comparator pulses charge a capacitor through a transistor, the capacitor being periodically discharged through a resistor, once per crankshaft revolution. An increase of capacitor voltage beyond a very small amount progressively lowers the resistances provided by the transistors connected to the comparator inputs, acting on one of them simply through a transistor and on the other through a transistor and a current mirror circuit. In order to compensate for the temperature dependent leakage current of the transistor driven by the comparator output in order to charge the capacitor, a second current mirror is provided that prevents charging of the capacitor during the blocked-condition of the transistor in question. A supplementary voltage divider is connected through isolating series resistors to set the d.c. level of the comparator inputs when the transistors connected to these inputs are non-conducting.

Evaluation circuit for electrical signals

To positively allocate output signals from a transducer scanning marker elements arranged at a uniform distance from the center of a rotating disk, the markers are located around the circumference of the disk in accordance with a predetermined pattern, for example, uniformly distributed 30.degree. apart, or distributed with uniformly increasing relative distances, and an additional market element (33) and forming a reference marker is located in the zones between adjacent markers spaced from a neighboring marker element (21) of the plurality of marker elements by a distance which is substantially larger than the angular distance with respect to the marker element at the other side of the reference marker. The outputs from a pick-up sensor are evaluated by applying the outputs to two counters, counting a different clock rate, the count output of one of the counters being stored and compared with a subsequent count state of the other counter operating at a higher clock rate. If the second counter has not reached the previously stored count, a positive indication that the sense marker as the reference marker is obtained, permitting a comparator to switch over a transfer switch to route the sensor output to a line indicating that the marker was the reference marker; if the faster-counting counter has, however, reached the count state of a slower counter in the prior cycle, an indication is obtained that the marker is a regularly recurring one, thus permitting control of the transfer of the output from the sensor to a routing line indicating that the marker is a regularly recurring one. The count rates are preferably sufficiently different to accomodate expected variations in speed of rotation of the disk within the recurrence time between adjacent markers.

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Vaihingen, Germany

Rainer Bone